ChaoticBliss

Hi All,

So the other day I was driving home and while travelling at a constant speed the car had a minor sputter like the throttle was closing even though I was trying to accelerate. It happened twice and then went away so I didn't think much of it.

Today I was out for a long drive and about 45 mins into the drive the stuttering came back but this time very severe. The car started bucking while driving at a constant speed and during acceleration. If I pushed the clutch in the car would stall out unless I kept the throttle significantly open. I nursed it for a while and then eventually it totally stalled out as I approached a stop sign. I got it restarted and it behaved much better for the rest of the drive home but when I pull into the garage is just stalled out again. (This stall out had no warning, it was idling fine and then just died). It restarted okay after that. During all this the oil pressure looked fine.

Does anyone have any suggestions as to things I can start checking?

Thanks

Tmistry

I'd replace your DME relay. Also check the connections to coils, plugs and the secondary distributer belt.

Another obvious one, but has the fuel filter been changed lately? Don't this would cause a problem out of the blue, but still.

First thing I'd do is swap the DME then take it for a very spirited drive.

justin-in-athens

I'm going with dirty fuel filter/failing pump.

C4inLA

+1 DME relay, have a spare at minimum..... Cheapest diagnostic test you'll ever have

Goughary

Dme relay. If it were coils, you'd likely have Christmas tree. So try that first.

540964

https://rennlist.com/forums/964-foru...rness-mod.html

Goughary

Good call. I always forget about that one...

Duck

Does the DME relay really have those issues? I would think that a relay would either stick so that the car does not start. Does it really cause the car to shutter?

Duck

Depends on MY of OP if a possible issue.

Duck

I did have a similar issue with coils going bad. Are they original black coils?

What about a failing fuel pressure regulator?

Tmistry

In my experience, yes, a shudder occurred occasionally and this was remedied with a new DME. I have a 1990 c2 coupe.

Also, perhaps a mental thing on my part, but a good aggressive drive smooths out the car. Taking the tach to 6,000 through the gears seems to reset things.

ChaoticBliss

Thanks all for the suggestions thus far. I will try a new DME first and see what happens. The DME didn't occur to me at first because it really feels like a fueling issue.

The car is a 89 C4 btw and it was being driven hard at the time this happened.

ChaoticBliss

The coils are black. Not sure then they were last changed. I'll have to go through the records.

Ya my initial thoughts were fuel pump or regulator since it felt similar to th car running out of fuel. It would bog down for seconds at a time then studder back to life for a few seconds .

Duck

Always good to have a spare DME relay if that does not end up to be the problem.

Good luck.

Steve Weiner-Rennsport Systems

Yessir, they certainly do and it's well documented. Please remember this relay controls power to both the ECU and fuel pump. Any SLIGHT interruption in power will cause the engine to cut out or "stutter".

This is why we STRONGLY recommend carrying a spare relay.